Organic electronic devices are present in many different kinds of electronic equipment. In such devices, an active layer is sandwiched between two electrical contact layers. At least one of the electrical contact layers is light-transmitting so that light can pass through the electrical contact layer. One type of electronic device is an organic light emitting diode (OLED), which holds promise for display applications due to its high power conversion efficiency and low processing costs. Such displays are especially promising for battery-powered, portable electronic devices, including cell-phones, personal digital assistants, handheld personal computers, and DVD players. These applications call for displays with high information content, full color, and fast video rate response time in addition to low power consumption.
OLED's typically contain electroluminescent (EL) layers arranged between an anode and a cathode. Types of electroluminescent materials which have been used in OLED's include fluorescent dyes, fluorescent and phosphorescent metal complexes, conjugated polymers, and mixtures thereof. Several classes of luminescent polymers have also been disclosed. These include, for example, poly(1,4-phenylene vinylene) and derivatives; polythiophenes, especially, poly(3-alkylthiophenes); and poly(p-phenylenes). Alkyl and dialkyl derivatives of polyfluorene have also been disclosed.
There is a continuing need for active compounds having the necessary efficiency and color. In particular, blue-emitting polymers are desirable.